Hitherto, such organic silicon compounds as alkylalkoxysilane compounds and fluoroalkylalkoxysilane compounds have been known to be useful as surface treating agents, fiber treating agents, and coating additives. Especially, it has been known that when a fluoroalkylalkoxysilane compound is used to treat a surface of an inorganic material (for example, glass, metal, or oxide) for the purpose of controlling water repellency, oil repellency or sliding properties (slidability of droplets) of the surface, covalent bonds formed between the alkoxysilane compound and the surface hydroxyl group of the inorganic material enable strong bonding between the fluoroalkylalkoxysilane compound and the inorganic material, whereby the weather resistance and retention of the modified surface properties are improved (see Non-Patent Document 1: “Silicone Handbook,” Edited by Itoh Kunio, Nikkan Kogyo Shimbun, Ltd., p. 79, line 9 to p. 80, line 5).
Where a fluoroalkylalkoxysilane compound is used for surface treatment, the compound is very effective in improving the static contact angle representing water repellency and oil repellency. In this case, however, the angle at which a droplet starts sliding along the surface treated (sliding angle) as well as the hysteresis (θA-θR) obtained from the advancing contact angle (θA) and receding contact angle (θR) are high; in other words, the dynamic contact angle is insufficient. The dynamic behavior is particularly important as an index to sliding properties (droplet removal performance), and an improvement thereof is being requested.
For enhancing lubricity, there have been developed alkoxysilane compounds having a perfluoropolyether group (see Patent Document 1: JP-A S63-250389). The alkoxysilane compounds, however, have been unsatisfactory in balance between the water and oil repellency and the sliding properties.
For realizing high water repellency and oil repellency by use of a short fluoroalkyl chain, there have been developed fluorine-containing acrylate compounds having two fluoroalkyl chains (see Patent Document 2: JP-A 2008-297400). Although these acrylate compounds have polymerizing properties, they lack reactivity with inorganic materials and, hence, they cannot impart water repellency, oil repellency and sliding properties to inorganic materials such as glasses, silicon wafers and fillers.